In recent years, tens of thousands of homes, commercial and institutional buildings have sustained severe structural damage due to the aggregates used in construction not being inert. An excess of naturally occurring reactive iron sulfides in the rock, is all that it takes to cause devastation within a few years of construction. These largescale problems have occurred in the United States, Canada and Ireland, despite these countries having well established building codes and standards. A new book explores how excess sulfides, mainly pyrite and pyrrhotite, in aggregates can be defined and identified in advance and it describes how the risk of future damage can be quantified. In keeping with the theme of Pyrite & Pyrrhotite, the book will also feature some innovative research into sustainable uses of pyrite.